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Notes 3.2

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magma chamber - a chamber that holds the magma
pipe - tubes that connects the magma to the surface
vent - a opening on the volcano
lava flow - the part that is covered with lava as it flows out of the vent
crater - a bowl shaped part on top of the volcano that collects magma
silica - silica is a element that is formed by oxygen and silicon
pahoehoe - a lava that flows vary fast, when cooled it shapes like ropes
aa - a lava that flows very slow, when cooled it forms blocks
pyroclastic flow - an explosion of gases, "bombs", ash, cinders, and rocks
active - a volcano that can erupt in the future
dormant - a volcano that is "asleep"
extinct - a volcano that is "dead"
hot spring - a stream of water that shoot up at a certain time
geyser - a water fountain that erupts from the ground
geothermal energy - heat energy made by heated (by magma) steam or water

Outline

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Introduction

• Hawaii's goddess, Pele
  • Pele is the destroyer and creator of the Hawaiian island
  • Pele lives under active volcanoes
  • If Pele is mad, she shoots out lava

How Magma Reaches Earth's Surface

• magma rises
  • because magma is less dense than the solid material, magma can flow through the cracks
  • the magma rises until it reaches the surface
• a volcano erupts
  • When a volcano erupts, it is like carbon dioxide released from soda
  • When a volcano eruption happens, the gasses in the magma flows out carrying the magma with them

Inside a Volcano

• the magma comes from a pocket called a magma chamber
• in order to let magma travel reach the surface, the magma travels through the pipe
• the point when the magma gets out the pipe is called the vent
• the magma then is collected in a bowl-shaped area on top of the volcano called the crater
• the magma that reaches the top is called lava
• the stream of lava that flows to land is called lava flow

Characteristics of Magma

• some magma flows very slowly, because it is very thick
• some flows almost as fast as water, because it is very thin
• the hotter the magma, the the faster it flows
• some magma are so sticky that it won't flow very far
• some magma produces dark colored lava

Types of Volcanic Eruptions

• quiet eruptions
  • runny lava flows quietly out of the crater
  • quiet eruptions form two different types of lava
    • pahoehoe
      • pahoehoe is a fast-moving lava
      • when cooled, forms wrinkles, "rope", and billows
    • aa
      • when aa is cooled, it forms bumpy rocks
• explosive eruptions
  • the explosion sends out gases, "bombs", ash, cinders, and rocks

Stages of a Volcano

• there are three kinds of volcano
  • active
    • a volcano that can erupt in the future
  • dormant
    • a volcano that is "sleeping"
  • extinct
    • a volcano that won't erupt

Other Types of Volcanic Eruption

• there are two other different kinds of volcanic eruption
  • hot spring
    • a hot spring is a pool of water formed by heated ground water seeping through the earth
  • geyser
    • a fountain heated by magma

Monitoring Volcanoes

• geologists monitor volcanoes by:
  • they use tiltmeter, laser-ranging device, and other devices to level the slight movement
  • they take temperatures from ground water, so they can see if the magma is getting hotter

Volcano Hazards

• people live near Mount St. Helens got careless and forgot about it, until it woke up from its 123-years sleep
• both quiet and explosive eruptions are dangerous
  • quiet eruptions bury citys, sets fire, and cause difficult breathing
  • volcanic ash can bury citys, clog car engins, and damage crop
  • if the ash is wet itis badd day for you! Damp ash can collaps roofs